1. Field of the Invention
The present invention relates to a wireless base station, a relay station, and a bandwidth allocation method. The present invention is suitably used for a wireless communication system which is obtained by introducing the relay station to the wireless communication system specified in IEEE 802.16.
2. Description of the Related Art
At present, wireless communication systems utilizing wireless communication paths for communication, such as WCDMA and CDMA2000 as a representative of systems, are in widespread use all over the world. The wireless communication system described above is provided with a plurality of wireless base stations, and a wireless terminal performs communication with other communication apparatus (a communication terminal) through any of the wireless base stations. If the wireless terminal comes close to an edge of a service area of the wireless base station which has started the communication, the wireless terminal can maintain the communication by performing a handover of wireless terminals in adjacent areas.
For example, technologies such as code division multiplex, time division multiplex, and orthogonal frequency division multiplex (OFDM and OFDMA, etc.) are employed for a wireless communication method. Thus, in general, a plurality of the wireless base stations can be connected to one base station simultaneously.
However, high-speed communication may not be possible even if the wireless terminal is in a service area of the wireless base station because a wireless environment is not excellent when the wireless terminal is near a border of the areas. Also, even though the wireless terminal is inside the area, there is a factor disturbing the transmission of wireless signals because of buildings and the like. Thus, there may be an area (a so-called blind zone) in which an excellent wireless connection between the wireless base station and the wireless terminal is difficult.
Therefore, there has been an idea proposed that a relay station is provided inside the service area of the wireless base station such a way that the wireless terminal can communicate wirelessly with the wireless base station through the relay station.
For a task group of 802.16j in particular, introducing the above described relay station (RS: Relay Station) is being discussed at the moment.
The described above matter related to IEEE802.16 is disclosed in, for example, IEEE Std 802.16-2004 and IEEE Std 802.16e-2005.